High-Frequency ultrasonic transducers, made from piezoelectric materials, are used in medicine to resolve small tissue features in the skin and eye and in intravascular imaging applications. High-frequency ultrasonic transducers are also used for imaging structures and fluid flow in small or laboratory animals. The simplest ultrasound imaging system employs a fixed-focused single-element transducer that is mechanically scanned to capture a 2D-depth image. Linear-array transducers are more attractive, however, and offer features such as variable focus, variable beam steering, and permit more advanced image construction algorithms and increased frame rates.
Although linear array transducers have many advantages, conventional linear-array transducer fabrication requires complex procedures. Moreover, at high-frequency, i.e., at or about 20 MHz or above, the piezoelectric structures of an array must be smaller, thinner and more delicate than those of low frequency array piezoelectrics. For at least these reasons, conventional dice and fill methods of array production using a dicing saw, and more recent dicing saw methods such as interdigital pair bonding, have many disadvantages and have been unsatisfactory in the production of high-frequency linear array transducers.